1. Field of the Invention
The present invention relates to a connector for establishing a continuous signal channel between a pair of separate signal wires or lines when first and second connector halves are coupled with each other.
2. Description of the Prior Art
Computer systems such as super computer, global servers, UNIX office computers, and the like, in general, allows a CPU (central processing unit) board to exchange electric signals with other boards such as controller boards, memory boards, and the like. Signal channels should be established between the CPU board and the other boards when the signal exchange is realized. Separable connectors are usually employed to connect a signal line of a board to a signal line of another board.
Separable connectors in general employ a pin-socket structure. A pin-socket structure usually comprises a conductive pin protruding from a plug component or first connector half, and a conductive socket embedded within a receptacle component or second connector half. When the plug component is coupled with the receptacle component, the conductive pin is received within the conductive socket. The conductive socket holds the conductive pin by its own elasticity. Such elasticity is supposed to keep a reliable electric connection between the conductive pin and socket.
In recent years, the operating speed or frequency of a CPU has increased, so that a higher transmission rate or frequency is also required for signal or data channels. A higher transmission rate inevitably causes noise to cross over the adjacent signal channels. If the transmission rate is further accelerated in signal or data channels, reaching a level over 1 or more GHz, for example, a severe countermeasure is required to prevent noise form crossing over adjacent signal or data channels.
In addition, signal channels should face a demand of a higher density in the future. However, a further reduction in size or dimension is hardly achieved in the aforementioned pin-socket structure. A smaller conductive socket cannot establish an elasticity enough to hold a conductive pin within the conductive socket itself. Less elasticity may induce, for example, a failure in an electric connection between the conductive socket and the conductive pin.
It is accordingly an object of the present invention to provide a connector, for establishing a signal or data channel, capable of meeting the demand of a higher transmission rate and a higher density of signal channels without any difficulty.
According to a first aspect of the present invention, there is provided a connector for a signal channel, comprising: at least a first conductive layer in a first connector half, a plurality of second conductive layers in a second connector half, to be alternated with the first conductive layer when the second connector half is coupled with the first connector half, and a plurality of signal lines arranged between the first and second conductive layers.
With the above structure, the first and second conductive layers, in combination, serve to establish a so-called strip line. Since the first and second conductive layers are adapted to function as ground or shield plates to absorb noise of the respective signal lines, the signal lines can reliably be shielded from noise caused by signals passing through the adjacent signal lines. Accordingly, it is possible to reduce the space between the adjacent signal lines so as to achieve a higher density of the signal lines. In addition, the alternated first and second conductive layers easily achieve a multilayered structure so as to contribute to an increased number of signal lines.
The connector may further comprise a conductive wire disposed between the adjacent signal lines. The conductive wire serves to, in combination with the first and second conductive layers, surround the signal line so as to provide a structure similar to coaxial cable. Accordingly, the signal lines can be tightly shielded from noise caused by signals passing through the adjacent signal lines.
In place of the conductive wire, a conductive wall may be employed to connect the first and second conductive layers to each other between the adjacent signal lines. The conductive wall likewise serves to, in combination with the first and second conductive layers, completely surround the signal line so as to provide a true coaxial cable. Accordingly, the signal lines can be completely shielded from noise caused by signals passing through the adjacent signal lines.
According to a second aspect of the present invention, there is provided a connector for a signal channel, comprising: at least a first conductive layer in a first connector half; a first flexible insulation layer superposed on a surface of the first conductive layer; first signal lines extending on a surface of the first flexible insulation layer; at least a second conductive layer in a second connector half; a second flexible insulation layer superposed on a surface of the second conductive layer, the second flexible insulation layer being spaced from the first flexible insulation layer between the first and second conductive layers when the first and second connector halves are coupled with each other; and second signal lines extending on a surface of the second insulation layer, the second signal lines being connected to the corresponding first signal lines between the first and second connector halves are coupled with each other.
A flexible circuit board comprising the first flexible insulation layer and the first signal lines as well as a flexible circuit board comprising the second flexible insulation layer and the second signal lines may be employed to provide a so-called strip line. In the aforementioned manner, the first and second signal lines between the first and second conductive layers can reliably be shielded from noise caused by signals passing through the adjacent first and second signal lines. In addition, the alternated first and second conductive layers easily achieve a multilayered structure so as to contribute to an increased number of the first and second signal lines. Moreover, employment of the flexible circuit board also serves to prevent variation in electric characters such as a contact resistance and the like to the utmost.
In addition, the connector may further comprise: first conductive pads formed at tip ends of the first signal lines and located along a datum line intersecting, by a predetermined inclination angle, a lateral direction perpendicular to a longitudinal direction of the first signal lines; and second conductive pads formed at tip ends of the second signal lines, which extend on extensions of the first signal lines when the first and second connector halves are coupled with each other, and located along the datum line. With such a structure, the first and second connector halves can be coupled with or detached from each other, not only along the longitudinal directions of the first and second signal lines, but also along the lateral directions, perpendicular to the longitudinal directions, of the first and second signal lines.
Alternatively, the connector may further comprise: first conductive pads formed at tip ends of the first signal lines and located along a datum line intersecting, by a predetermined inclination angle, a lateral direction perpendicular to a longitudinal direction of the first signal lines; and second conductive pads formed at tip ends of the second signal lines, which extend across the first signal lines so as to reach the datum line when the first and second connector halves are coupled with each other, and located along the datum line. In the case where the first and second signal lines are designed to intersect each other by a predetermined inclination angle when the first and second connector halves are coupled with each other, the respective combinations of the first and second signal lines, connected to each other, may be designed to extend over a predetermined length. The length of the signal channels, each comprising the combination of the first and second signal lines, can be unified in the connector. Such a structure may contribute to avoidance of skews between the signal channels.
In order to keep a reliable contact between the first and second signal lines, the connector may further comprise a leaf spring interposed between the surface of the first conductive layer and the first flexible insulation layer so as to establish an elastic force for urging the first signal lines toward the second signal lines when the first and second connector halves are coupled with each other. Such a leaf spring may serve to keep enough contact pressure even when mechanical characters, such as the width and/or thickness, of the first and second signal lines are varied. The connector may accept variation in an electric character, such as a contact resistance, of the first and second signal lines without losing a reliable contact between the first and second signal lines.
In place of the aforementioned leaf spring, a common holding mechanism may be employed to keep together the first and second conductive layers, which are alternately superposed, when the first and second connector halves are coupled with each other. The common holding mechanism likewise allows the connector to accept variation in an electric character of the first and second signal lines without losing a reliable contact between the first and second signal lines. Moreover, the common holding mechanism may contribute to simplification of the structure of the connector even when an increased number of first and second conductive layers and/or the first and second signal lines are required in the connector.
The aforementioned connector may employ a connector half comprising: at least a conductive layer; a pair of flexible insulation layers superposed on opposite surfaces of the conductive layer; and a plurality of signal lines extending on surfaces of the respective flexible insulation layers. In addition, the connector may employ, in combination with the above connector half, a connector half comprising: a housing; at least a pair of conductive layers spaced each other within the housing; a pair of flexible insulation layers superposed on surfaces of the conductive layers facing each other; and a plurality of signal lines extending on surfaces of the flexible insulation layers.